The present invention relates in general to the same technology as the above-identified patents and patent applications. The above patents and patent applications are incorporated by reference in this application.
As more and more financial and other business transactions take place in offices and stores remote from a central accounting office, there develops a greater need for precise identification of the person involved in the transaction. For instance in the cashing of checks or in the identification of a person to determine whether or not they should be allowed into a restricted area, there is a greater need for unerring identification. Additionally with so many computer files which incorporate personal data concerning individuals, it is further important to assure that this data is not made available to unauthorized persons.
The present invention relates to an identification system which is a modification and improvement over those systems described in the above-identified applications and patents. A problem with earlier systems occurs when several identifier signals are presented to a reader at a timing so close together that the signals overlap thereby making it difficult for the reader to separate the signals. One feature of this invention is to provide improved means for such signal separation.
Another deficiency with earlier identifiers of this general type involves their inability to determine the direction of motion of the identifier, that is, whether there is occurring ingress or egress from a restricted area. It is a further feature of this invention to show means for determining in which direction the identifier is moving.
In earlier systems the identifier could be acquired by an unauthorized person thus allowing fraudulent or misleading transactions to occur because it is difficult at the point of sale or point of entry to detect and prohibit these improper transactions. The present invention incorporates within a memory information allowing verification that the proper person is using the identifier.
Earlier identifiers have also been susceptible to incorrect signal transmissions in the presence of noise which can reverse the nature of a bit in the transmission process, that is, a "one" can appear as a "zero" and vice-versa. The present invention incorporates redundant radio frequencies and a noise rejecting comparison circuit to reduce this risk and provide more reliable and faster signal transmissions.